Thin film sensor platform for on-chip detection of fluorescence-based aptamer assay

This work presents a bio-microsystem, based on thin film optoelectronic devices, for on-chip detection of fluorescence-based aptamer assay. The detection is achieved integrating on a single glass substrate amorphous silicon photosensors and a thin film interferential filter, while the aptamer-based biomolecular recognition is carried out in a microfluidic network functionalized with polymer brushes. To test the developed platform, aptamer 1.12.2 having high affinity toward Ochratoxin A molecules has been used in combination with the ruthenium complex [Ru(phen)2(dppz)]2+ intercalating dye. We found that the developed platform can perform the analysis by using a small volume of sample (about 10 μL) in short time (5 min) with a limit of detection equal to 1.56 ng/ mL. With respect to the existing literature, the reported system features compactness, high sensitivity and high versatility since the fluorophore-aptamer system may be used with different kind of analytes.